Two-Layer Forcepad Electrode Layout for Thin Dual Detection
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Solution Overview
Problem
Existing input devices that combine proximity and force detection, such as touchpads and forcepads, face challenges in achieving a thin design while maintaining effective detection capabilities, as they often require multiple layers of electrodes which increase thickness and complexity.
Innovation Solution
A two-layer input device design is implemented, where proximity receiver electrodes are on one single layer and force receiver electrodes are on another, with transmitter electrodes configured to transmit signals capacitively coupled to both, and a compressible layer is used between the force receiver electrodes and a ground plane to enhance detection capabilities while minimizing thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple layers of electrodes are used to achieve both proximity and force detection, then detection capabilities are improved, but device thickness increases
Solution Approach 1:
The patent combines proximity and force detection functionality into a single integrated sensor layer. The sensor layer contains both proximity transmitter segments and force transmitter segments, along with receiver electrodes that can detect both proximity signals and force-induced capacitance changes. This merging eliminates the need for separate electrode layers for each detection type, thereby reducing overall device thickness while maintaining dual detection capabilities.
Solution Approach 2:
The sensor layer is designed as a multi-functional component that performs both proximity detection and force detection. The same transmitter and receiver electrode structures are used for both detection modes by utilizing different signal processing pathways. The capacitive coupling mechanism serves dual purposes: detecting proximity through parasitic capacitance changes and detecting force through direct capacitance modulation, making the sensor layer universal for both functions.
2Adaptability or versatility
If multiple layers of electrodes are used to achieve both proximity and force detection, then detection capabilities are improved, but device complexity increases
Solution Approach 1:
The patent merges the electrode structures for proximity and force detection into a single sensor layer, reducing the number of discrete components and inter-layer connections. The transmitter segments and receiver electrodes are arranged in a unified pattern that serves both detection functions, simplifying the overall device architecture compared to separate electrode layers for each detection type.
Solution Approach 2:
The sensor layer is designed as a universal structure that performs both proximity and force detection using the same physical components. The transmitter and receiver electrodes function in both detection modes through different signal processing pathways, eliminating the need for separate dedicated electrode sets and reducing device complexity.
3Length of stationary object
If a thin design is implemented, then device thickness is reduced, but signal detection accuracy may deteriorate
Solution Approach 1:
The patent employs a thin-film sensor layer constructed using flexible printing techniques on a substrate. This thin-film structure maintains compact device thickness while preserving effective capacitive coupling between transmitter and receiver electrodes. The flexible film architecture allows for close proximity of electrode elements without requiring bulky multi-layer constructions, thereby maintaining signal detection accuracy in a thin profile.
Solution Approach 2:
The patent optimizes the capacitive coupling parameters within the single sensor layer to achieve accurate signal detection. By adjusting the spacing, area, and configuration of the transmitter and receiver electrodes within the thin layer, the system maintains strong capacitive signals despite the reduced thickness. The compressible layer further enhances this by providing controlled mechanical coupling that amplifies force-induced capacitance changes without increasing overall device thickness.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design allows for improved usability with both proximity and force detection capabilities in a thinner form factor, reducing the number of layers needed and enhancing signal detection accuracy, thus addressing the thickness constraints of traditional multi-layer designs.
Implementation Method 1
the proximity transmitter segments capacitively coupled to the proximity receiver electrodes
Implementation Method 2
the force transmitter segments capacitively coupled to the force receiver electrodes
Implementation Method 3
a compressible layer interposed between the second single layer and the ground plane
Data Source
AI summary
An input device sensor includes proximity receiver electrodes on a first single layer, force receiver electrodes on a second single layer, and transmitter electrodes configured to transmit a transmitter signal. Each transmitter electrode includes proximity transmitter segments linearly arranged on the first single layer and separated by the proximity receiver electrodes. The transmitter electrodes further each include force transmitter segments linearly arranged on the second single layer and separated by the force receiver electrodes, the force transmitter segments connecting adjacent proximity transmitter segments in the proximity transmitter segments. The input device sensor further includes a first ground shield on the first single layer, the first ground shield shielding the force receiver electrodes from the proximity transmitter segments. The input device sensor further includes a ground plane, and a compressible layer interposed between the second single layer and the ground plane.